GNAI1 and HIV-1 infection: Using PTX (an inhibitor of Gi protein), we evaluated whether Gi protein blockade (leading to a subsequent extra-amplification of the cAMP levels) could change the VIP and PACAP inhibitory effect on HIV-1 infection, indicating that cAMP pathway activation is a component of the cellular signaling involved in the neuropeptide effects on HIV-1 production in macrophages.